1. Field of the Invention
The present invention pertains to hand-held computers, such as personal data assistants (PDAs). More particularly, the present invention is directed to providing automated telecommunications for mobile computers.
2. Discussion of Related Art
Desktop computers are designed to be used at a desk. Portable or "laptop" computers are designed to be carried from place to place, but are used in essentially the same way as desktop computers, with the computer device resting on some fixed surface. In contrast, hand-held or "mobile" computers are computers designed to be used on the move. There are three common configurations of these mobile computers: pistol-grip computers, such as those made by Telxon.TM.; keyboard-based palmtop computers such as the Psion Organizer.TM.; and tablet computers, such as Apple's Newton.TM. or 3Com's Palm Pilot.TM. that provide an iconic "GUI" interface and accept handwritten information. The latter two, particularly the tablet computers, are also referred to as "PDAs".
Hand-held computers are widely used for inventory control, in the publishing and retail grocery businesses, for example, and often share a pistol-shaped housing with devices that read and store bar-code information. Palmtop computers are essentially desktop computers including the conventional features of the desktop computer: display, keyboard, etc., but greatly reduced in size and usually housed in an open-faced case, rather than the "clamshell" folding case used for the larger, "laptop" computers. Tablet computers are similar to the palmtop computers in size, but they are computerized, paper-less note pads: the user `writes` on the tablet with a stylus, and the tablet interprets the movement of the user's stylus as commands and data. The tablet computers are often GUI driven, so that the stylus can be used to actuate GUI "button" icons, even operate a GUI keyboard.
All mobile computers are designed to be as lightweight as possible. This is particularly problematic for power supply design, and output devices, generally, require substantial power supply capacity. Having very little power to spare, these mobile computers have spawned a flood of peripheral and accessory devices that offer various functions expanding the built-in input and output (I/O) capabilities of mobile computers as local area network (LAN) and wide-area network (WAN) telecommunications terminals, as well as, printer terminals. For example, U.S. Pat. Nos. 5,606,594 and 5,625,673 disclose communications accessories that provide an enclosure for and add functions to a PDA unit. However "accessories", unlike peripheral devices, do not have the computing power to provide an application program interface (API) for the mobile host computer.
With the rise of the Internet and the advent of Voice-over-IP (VoIP) telephony, providing computer-based telecommunications now demands more processing capacity than ever before. In addition to the basic serial data-over-voice (DOV) connectivity work done by conventional modems that are available as accessories, digital call-control features such as conference calling require API support. Also, conversions turning audio and other signals into bit streams, bit streams into bytes and bytes into IP packets, as well as the reverse process turning received IP packets back into sound, text or images, require API support. Mobile computers simply do not have the computing power to provide the API support nor the power needed to support the data speeds and bandwidths required for initiating and maintaining the communications services required for many current IP applications. Audio and video, in general, and VoIP audio in particular, have stringent real-time performance standards and require API support for their specialized high-speed control and data conversion functions.